To analyze microbiological data from MRSA samples obtained through the emergency department from 2001-2005. There is a strong clinical suspicion that we are now seeing an outbreak of a new strain of MRSA and we plan to better characterize the Vancouver population and complete a chart review to assess specific associated factors.

Pulse field gel electrophoresis, SCC mec typing, antibiotic susceptibilities, presence of the Panton-Valentine Leukocidin gene will be carried out. Clinical manifestations and associated factors will be assessed via chart review. These include: recent antibiotic use, recent hospitalization, IV drug use, HIV status, number of co-morbidities identified, presence of soft tissue abscess, post operative status, presence of bacteremia, residence in Vancouver's downtown eastside (an area of particularly low socioeconomic status).

Inclusion Criteria:

• Patient had a microbiological sample submitted from the emergency department of the study hospital from 2001- 2005 which grew MRSA.

Patients with a microbiological sample submitted from the emergency department of the study hospital.